MEMORNDUM
TO: Mary Beth Broeren, City of Huntington Beach
FROM: Hasan Nouri, Rivertech Inc.
DATE: September 10,2002
SUBJECT: Responses to Comments by the California Coastal Commission
on Parkside Estates "Conceptual" Water Quality Control Plan
I have just received the comments by the State of California Coastal Commission (Coastal Commission) dated September 9, 2002 on the Parkside Estates Water Quality Control Plan. Given the time constraints I will attempt to provide you with my responses to the best of my ability.
We appreciate the information provided to us by the staff of the Coastal Commission on our 1998 Conceptual Water Quality Control Plan (1998 Report) and the 2002 Addendum. The comments are useful and will be integrated in our future plans. However, the following points must be mentioned
In 1998 Rivertech Inc. at the request of Shea Homes provided numerical analysis of pollutant loads from Parkside Estates under Existing and Developed Conditions. None of the planned residential developments at that time provided this level of detail. In fact, CEQA documents typically only provide the general level of analysis provided on pages 5-138, 5-141 through 5-142 of the EIR including mitigation measures 2 and 3 (recommended by RWQCB) which require the applicant comply with NPDES requirements and obtain the necessary permits. The 1998 report was only conceptual and at that time the alternatives using innovative technology to treat urban runoff was limited. Continuous Deflection Separation (CDS) was a (state of the art) device at the time. In 1998 the CDS manufacturer had advised us that the system was capable of removing up to 90% of the pollutants. Research during the past 4 years on CDS units shows that the efficiency of the equipment to remove pollutants is more limited.
Realizing this fact about CDS, our 2002 Addendum identifies within Section Best Management Practices (BMPs) including a treatment train which will reduce the water quality impacts to less than significant levels. As required by the City conditions, prior to the issuance of grading permits, we will prepare an Urban Runoff Management Plan (URMP) that will describe and identify that treatment train. Consistent with the requirements of the State of California Regional Water Quality Control Board, Santa Ana Region (RWQCB-SR) the URMP will include numerical analysis of pollutant loads that would be contributed under existing and developed conditions. The URMP will also identify and describe mitigation measures that would reduce pollutant loads to insignificant levels. Unfortunately, the comments by the Coastal Commission make no mention of the URMP and our future plans. Also, it should be noted that the analysis included in the 1998 report assumes that only the 21.8 acres of existing development contributes urban pollutants to the Slater Channel and not the undeveloped Parkside Estates area. The staff of the Coastal Commission has misinterpreted this information and understands that urban pollutant loads calculated under Existing Conditions is from an area that includes the existing development of 21.8 acres as well as the undeveloped Parkside Estates site.
In addition to the BMPs and the treatment train described in Section 3
of our 2002 Addendum we are currently investigating the use of sand filters
for treating urban runoff from the planned Parkside Estates. After the implementation
of URMP we are confident that the requirements of the RWQCB-SR and the Coastal
Commission will be satisfied.